Pump for measuring pressure of fluid to be transferred, fluid transport system using the same, and method for operating the system

ABSTRACT

The present invention discloses a pump for measuring a pressure of fluid to be transferred, a fluid transport system using the same, and a method for operating the system. The pump includes a pumping portion alternately generating a positive pressure and a negative pressure; a first diaphragm which is provided on one side of the pumping portion and of which a shape is changed as the positive pressure and the negative pressure are alternately generated; a transport chamber which sucks and discharges a transport target fluid corresponding to the deformation of the first diaphragm; a second diaphragm which is provided on the other side of the pumping portion; a monitoring chamber which is provided on one side of the second diaphragm and of which a pressure changes corresponding to the deformation of the second diaphragm; and a pressure measuring portion measuring a pressure change of the monitoring chamber.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.16/822,498 filed Mar. 18, 2020 which claims priority to and the benefitof PCT Patent Application No. PCT/KR2018/010976 filed on Sep. 18, 2018,and Korean Patent Application No. 10-2017-0120527 filed in the KoreanIntellectual Property Office on Sep. 19, 2017, the entire contents ofwhich are incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a pump for measuring a pressure offluid to be transferred, a fluid transport system using the same, and amethod for operating the system.

2. Description of the Related Art

A fixed volume pump is a pump that constantly transports a liquid perunit time. The Pump can be divided into a diaphragm pump (membranepump), a gear pump, a peristaltic pump, a syringe pump, and the likeaccording to its principle of operation, and is used in a wide range ofindustries.

In particular, the diaphragm pump pulsates a separating plate of anelastic thin film to perform suction or discharge of a liquid by avolume change, and the diaphragm pump is used for a small capacity pumpor a fixed volume pump for drug injection or the like. In thereciprocating pump, a flow of the liquid is intermittent by naturebecause the suction and discharge of the liquid are repeatedlyperformed. As a result, inertia is generated in the liquid flowing in aflow path, vibration is continuously generated in the flow path, andthereby the pump may malfunction due to blockage of the flow path or gasgeneration. In addition, fine foreign matters can also block the flowpath, thereby causing the pump to malfunction. Such unstable drivecauses difficulties especially in using the diaphragm pump for injectingdrugs into the human body.

In an example, an intrathecal drug administration system (ITDAS) iswidely used as an intra-body implantable drug infusion pump. Theintrathecal drug administration system is mainly used for treatment ofcancer pain or chronic pain with severe pain, and is also utilized for apatient with cerebral palsy and spasticity symptoms. In such anintra-body implantable drug infusion pump, an extent to which thecatheter blockage or pump malfunction is related to the patient's lifeis very important. Therefore, a method of embedding a pressure sensor inthe flow path for monitoring the pump malfunction has been developed.However, embedding the sensor in the flow path may contaminate thetransport target fluid in the flow path, and thus it is difficult forthe sensor to be applied to the intra-body implantable drug infusionpump.

In this regard, U.S. Patent Application Publication No. 2013-0121880(Title of the Invention: AUTOMATIC ANALYZER) discloses contents in whichvibration of a specific frequency is given through a pressuretransmission medium (vibrator) in a flow path, and then a pressuresensor provided outside the flow path measures an amplitude or a phaseof a specific frequency to detect whether or not the liquid is normallysucked into a nozzle. However, because the vibrator or the like has tobe further provided, there is still a limitation in that a size of thepump is increased, and when a sample is injected into the human body,the human body may be harmed by the vibration in the flow path.

SUMMARY OF THE INVENTION

The present invention is to solve the problems described above of therelated art, and an object of the present invention is to provide a pumpformed to efficiently measure a pressure of a flow path withoutcontaminating a liquid in the flow path, a fluid transport system usingthe same, and a method of operating the system. However, the technicalproblem to be solved by the present example is not limited to thetechnical problem as described above, and other technical problems mayexist.

As technical means for solving the technical problem described above, afirst aspect of the present invention is a pump including: a pumpingportion alternately generating a positive pressure and a negativepressure; a first diaphragm which is provided on one side of the pumpingportion and of which a shape is changed as the positive pressure and thenegative pressure are alternately generated; a transport chamber whichis provided on one side of the first diaphragm, and sucks and dischargesa transport target fluid corresponding to the deformation of the firstdiaphragm; a second diaphragm which is provided on the other side of thepumping portion and of which a shape is changed as the positive pressureand the negative pressure are alternately generated; a monitoringchamber which is provided on one side of the second diaphragm and ofwhich a pressure changes corresponding to the deformation of the seconddiaphragm; and a pressure measuring portion measuring a pressure changeof the monitoring chamber.

In addition, a second aspect of the present invention is a fluidtransport system including: a pump including a first diaphragm and asecond diaphragm which are provided on both sides of a pumping portionalternately generating a positive pressure and a negative pressure, andof which shapes are changed according to the positive pressure and thenegative pressure, a transport chamber which sucks and discharges atransport target fluid according to the shape change of the firstdiaphragm, a monitoring chamber of which a pressure changes according tothe shape change of the second diaphragm, and a pressure measuringportion measuring a pressure of the monitoring chamber; a reservoir inwhich the transport target fluid is stored; a suction path that is afluid transport path through which the transport target fluid dischargedfrom the reservoir is sucked to the pump; a discharge path that is afluid transport path of the transport target fluid discharged from thepump; and a control circuit detecting abnormality of the pump bymonitoring a pressure value measured by the pressure measuring portion.

In addition, a third aspect of the present invention is a method ofoperating a fluid transport system using the pump of the first aspect,the method including: (a) a step of alternately supplying voltages ofdifferent polarities to a pumping portion such that at least a part of afirst diaphragm moves forward and backward, and thereby a transporttarget fluid is sucked and discharged into a transport chamber providedon one side of the first diaphragm; (b) a step of monitoring a pressurechange of a monitoring chamber provided on one side of a seconddiaphragm; and (c) a step of detecting abnormality of the pump based ona change pattern of pressure values measured for a predetermined timeand an average value of the pressure values measured for thepredetermined time. In this case, at least a part of the seconddiaphragm moves forward and backward in a same direction as the firstdiaphragm as voltages of different polarities are alternately suppliedto the pumping portion.

A fourth aspect of the present invention is a computer-readablerecording medium on which a program for implementing the method of thethird aspect is recorded.

According to the problem solving means of the present inventiondescribed above, an air layer through which the same pressure as thepressure transmitted to the transport target body is transmitted to thepump is formed, and a pressure sensor is disposed in the air layer toefficiently measure the pressure value transmitted to the transporttarget fluid. Furthermore, in the fluid transport system using the pump,it is possible to effectively detect whether or not the pump operatesand the flow path is blocked by monitoring the change shape of thepressure value.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view illustrating a configuration of a pump according to anexample of the present invention.

FIG. 2A(i) is a view illustrating a configuration of a pumping portionaccording to an example of the present invention, and FIG. 2A(ii) is anexploded view illustrating the pumping portion.

FIGS. 2B(i) and 2B(ii) are views illustrating an example in which a flowof a fluid in the pumping portion changes according to a reversibleelectrochemical reaction according to an example of the presentinvention.

FIG. 3A is a view illustrating an experimental environment forexperimenting a correlation between a pressure change appearing in amonitoring chamber according to driving of the pump and a pressurechange measured in a transport target fluid, and FIG. 3B is a graph forexplaining an experimental result of FIG. 3A.

FIG. 4 is a block diagram illustrating a configuration of a fluidtransport system using the pump of FIG. 1 according to an example of thepresent invention.

FIG. 5 is a view for explaining a principle that the transport targetfluid moves in the fluid transport system according to an example of thepresent invention.

FIG. 6 is a flowchart illustrating a method of detecting abnormality ofa pump by a control circuit according to an example of the presentinvention.

FIG. 7 is a view illustrating a fluid transport system used in theexperiment.

FIG. 8 is a graph for explaining an experimental result of detectingnon-operation of the pumping portion using the fluid transport system ofFIG. 7.

FIGS. 9 and 10 are graphs for explaining experimental results ofdetecting blockage of the flow path using the fluid transport system ofFIG. 7.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, examples of the present invention will be described indetail with reference to the accompanying drawings so that those skilledin the art may easily implement the present invention. However, thepresent invention may be embodied in many different forms and is notlimited to the examples demonstrated here. In the drawings, portionsirrelevant to the description are omitted in order to clearly describethe present invention, and like reference numerals designate likeportions throughout the specification.

In the present specification, when a portion is “connected” to anotherportion, it includes not only “directly connected”, but also“electrically connected” with another element interposed therebetween.

Throughout the present specification, when a member is located “on”another member, this includes not only a case in which one member is incontact with another member but also a case in which further anothermember exists between the two members.

In the present specification, when a portion “includes” a certainconfiguration element, it means that it further includes otherconfiguration elements, without excluding the other configurationelements unless otherwise stated. The terms “about”, “substantially”,and the like as used throughout the present specification of the presentinvention are used at, or in proximity to, the numerical values whenmanufacturing and material tolerances inherent in the meanings mentionedare given, and in order to prevent unscrupulous infringers from unfairuse, accurate or absolute figures are used to aid the understanding ofthe present invention. As used throughout the present specification ofthe present invention, a term “step” or “step of” does not mean “stepfor”.

FIG. 1 is a view illustrating a configuration of a pump according to anexample of the present invention.

Referring to FIG. 1, a pump 10 according to an example of the presentinvention includes a pumping portion 13 alternately generating apositive pressure and a negative pressure; a first diaphragm 11 which isprovided on one side of the pumping portion 13 and of which a shape ischanged according to the positive pressure and the negative pressure; atransport chamber 14 which sucks and discharges a transport target fluidcorresponding to the shape change of the first diaphragm 11; a seconddiaphragm 12 which is provided on the other side of the pumping portion13 and of which a shape is changed according to the positive pressureand the negative pressure; a monitoring chamber 15 of which a pressurechanges corresponding to the shape change of the second diaphragm 12;and a pressure measuring portion 16 measuring a pressure change of themonitoring chamber 15. The monitoring chamber 15 may be filled with gasor a fluid, and the pressure measuring portion 16 may be a pressuresensor that measures a pressure of the gas or the fluid.

First, the pumping portion 13 may include one or more configurationelements that alternately generate the positive pressure and thenegative pressure. For example, the pumping portion 13 may include atleast one configuration element that alternately transports the negativepressure and the positive pressure with the first and second diaphragms11 and 12 by causing the fluid and/or gas with which the pumping portion13 is filled to reciprocate by transforming a rotational force of amotor (not illustrated) into a reciprocating motion.

Alternatively, the pumping portion 13 may include at least oneconfiguration element that causes the fluid and/or the gas toreciprocate through an electrochemical reaction but is not limitedthereto. For example, the pumping portion 13 may be implemented using anelectroosmotic principle. In this case, the pump 10 is an electroosmoticpump which is operated on a principle that the fluid moves by theelectroosmotic phenomenon generated when a voltage is applied by usingelectrodes at both ends of a capillary tube or a porous membrane. Unlikea mechanical pump, the electroosmotic pump has advantages that there isno mechanical moving portion thereby being silent and effectivelycontrolling a flow rate in proportion to the applied voltage.

FIG. 2A(i) is a view illustrating a configuration of the pumping portionaccording to an example of the present invention, and FIG. 2A(ii) anexploded view illustrating the pumping portion.

As illustrated in FIGS. 2A(i) and 2A(ii), the pumping portion 13according to an example of the present invention includes a membrane 23;a first electrode 21 and a second electrode 22 provided on both sides ofthe membrane 23, respectively; and strips 24 and 25 in which the firstand second electrodes 21 and 22 are stored, and which transmit electricpower to the first and second electrodes 21 and 22. The strips 24 and 25have respective connecting members 24 a and 25 a connected to the powersupply portion 27 to transmit the electric power supplied from the powersupply portion 27 provided outside the pump 10, to the first and secondelectrodes 21 and 22.

The pumping portion 13 generates a positive pressure and a negativepressure through a flow of the fluid between the membrane 23, and thefirst and second electrodes 21 and 22.

Specifically, as illustrated in FIG. 2A(i), the membrane 23 is installedin the fluid path portion 26 through which the fluid moves, and asillustrated in FIG. 2A(ii), the membrane 23 is formed of a porousmaterial or structure to allow the movement of the fluid. The firstelectrode 21 and the second electrode 22 are provided on both sides ofthe membrane 23 on the fluid path portion 26, and the first electrode 21and the second electrode 22 may include a conductive polymer in which ananionic polymer is mixed. Like the membrane 23, the first electrode 21and the second electrode 22 are formed of a porous material or structureto allow the movement of the fluid.

When a voltage is supplied to first and second electrodes 21 and 22, avoltage difference between the first electrode 21 and the secondelectrode 22 causes a redox reaction to occur in the first electrode 21and the second electrode 22, and thereby a charge balance is broken. Atthis time, charges are balanced by moving cations in the first andsecond electrodes 21 and 22. In this case, any one of the firstelectrode 21 and the second electrode 22 may generate cations through anelectrochemical reaction, and the other may consume the cations. Here,the cations generated and consumed during the electrochemical reactionmay be monovalent cations, but are not limited thereto, and may includevarious ions such as hydrogen ions (H+), sodium ions (Na+), potassiumions (K+), and the like.

When the ions move according to the redox reaction through the membrane23, the fluid may move along the fluid path portion 26. In this case,the membrane 23 may allow the movement of ions as well as the fluid.Therefore, when the electric power is supplied to the first and secondelectrodes 21 and 22, the fluid and ions may be moved from one side tothe other side of the membrane 23 or from the other side to one sidethereof.

In addition, a conductive polymer may be electrodeposited on the firstelectrode 21 and the second electrode 22. In the pumping portion 13, theconductive polymer includes a macromolecule polymer, that is, an anionicpolymer. In the redox reaction of the first and second electrodes 21 and22, since the anionic polymer is fixed and cannot be moved, the cationsin the fluid move and balance the charge. That is, when the conductivepolymer matrix is neutral during the reduction reaction of the negativeelectrode, the cations present in the fluid are introduced to balancethe charge of the fixed anionic polymer. In other words, during theredox reaction of the first and second electrodes 21 and 22, the anionpolymer does not move, but the cations in the fluid move. The cationscan easily pass through the membrane 23 by action of an attraction forcewith the negatively charged membrane 23, thereby causing a rapid redoxreaction. This means that the pump 10 can move the fluid at high speed.

In this case, the conductive polymer may be formed throughpolymerization of monomers in the fluid including the anionic polymer.Alternatively, the conductive polymer may be synthesized throughelectrochemical oxidation or chemical oxidation using an oxidizingagent. In addition, the conductive polymer may be various polymershaving electrical conductivity or negative charge.

In addition, the first and second electrodes 21 and 22 may furtherinclude a carbon nanostructure such as carbon nanotube (CNT), graphene,and carbon nanoparticle. In the electrode electrodeposited a compositeof the conductive polymer including the carbon nanotube in the carbonnanostructure, the redox reaction may occur at a more stable and at ahigh speed. In addition, the first and second electrodes 21 and 22 mayfurther include metal oxides such as manganese oxide (MnOx), cobaltoxide (CoOx), nickel oxide (NiOx), ruthenium oxide (RuOx), andcomposites thereof. The first and second electrodes 21 and 22 formed ofthe metal oxides can be induced movement of cations through a redoxreaction.

Meanwhile, the conductive polymer included in the first electrode 21 andthe second electrode 22 may cause a reversible electrochemical reaction.That is, the first electrode 21 and the second electrode 22 may haveboth forward reaction and reverse reaction, respectively. The reversibleelectrode reaction may be performed by alternately supplying polaritiesof voltages to the first electrode 21 and the second electrode 22,respectively by the power supply portion 27.

FIGS. 2B(i) and 2B(ii) illustrate an example in which the flow of thefluid in the pumping portion changes according to a reversibleelectrochemical reaction according to an example of the presentinvention.

In addition, the first electrode 21 and the second electrode 22 may notonly change the flow of the fluid by utilizing an electrode materialhaving a reversible electrode reaction, but also can return anelectroactive material consumed by the positive reaction as theelectrode reaction occurs in the reverse direction, to its originalstate. As described above, the first and second electrodes 21 and 22 canincrease the life of the pump 10 by repeating consumption andregeneration.

Referring back to FIG. 1, the first and second diaphragms 11 and 12configured on both sides of the pumping portion 13 are non-limitingexamples and are formed of oil to form an oil gap, natural rubber formedof an elastic thin film, synthetic rubber, a metal plate, or the like.As the negative pressure and the positive pressure are alternatelygenerated according to the driving of the pumping portion 13, at least apart thereof moves forward and backward to transmit the negativepressure and the positive pressure to the transport chamber 14 and themonitoring chamber 15.

For example, the first diaphragm 11 transmits the negative pressure andthe positive pressure generated by the driving of the pumping portion13, to the fluid to be transferred (Hereinafter, referred to astransport target fluid). More specifically, when the negative pressureis generated, at least a part of the first diaphragm 11 moves backward(that is, when a part of the first diaphragm 11 moves toward themonitoring chamber 15 based on FIG. 1 (illustrated by a long dottedline)), the transport target fluid is sucked into the transport chamber14 and, on the contrary, when the positive pressure is generated, atleast a part of the first diaphragm 11 moves forward (that is, when apart of the first diaphragm 11 moves toward the transport chamber 14based on FIG. 1 (illustrated by a short dotted line)), the transporttarget fluid is discharged from the transport chamber 14.

In this case, suction and discharge of the transport target fluid areperformed through the suction port 14 a and the discharge port 14 bformed on one surface of the transport chamber 14. The suction port 14 aand the discharge port 14 b are respectively coupled to a suction valve17 and a discharge valve 18 which allow or block the flow of thetransport target fluid, so that the transport target fluid can be suckedthrough the suction port 14 a and can be discharged through thedischarge port 14 b. In other words, the suction valve 17 is closed whenthe first diaphragm 11 moves forward and is opened when the firstdiaphragm 11 moves backward, and the discharge valve 18 is opened whenthe first diaphragm 11 moves forward and is closed when the firstdiaphragm 11 moves backward. The suction valve 17 and the dischargevalve 18 may be, for example, check valves, but are not limited thereto,and may be open/close devices that operate opposite to each other. Inaddition, in the above description, the suction valve 17 and thedischarge valve 18 are described as being coupled to the pump 10, butthe suction valve 17 and the discharge valve 18 may be implementedintegrally with the pump 10.

Similar to the first diaphragm 11, the second diaphragm 12 repeatedlymoves backward and forward by the driving of the pumping portion 13.Accordingly, by the movement of the second diaphragm 12, an air pressurein the monitoring chamber 15 changes. That is, when the negativepressure is generated, at least a part of the second diaphragm 12 movesbackward (that is, when a part of the second diaphragm 12 moves towardthe monitoring chamber 15 based on FIG. 1 (illustrated by a long dottedline)) and thereby the pressure in the monitoring chamber 15 isincreased. Conversely, when the positive pressure is generated, at leasta part of the second diaphragm 12 moves forward (that is, moves towardthe transport chamber 14 based on FIG. 1 (illustrated by a short dottedline)), and thereby the air pressure in the monitoring chamber 15 isdecreased.

The pressure measuring portion 16 is provided inside the monitoringchamber 15 to detect the pressure in the monitoring chamber 15 toconvert the pressure into an electrical signal. For example, thepressure measuring portion 16 may be a pressure sensor that detects apressure value as the second diaphragm 12 is deformed, based on acapacity change, a magnetic force change, a resistance displacement, anda voltage displacement of the monitoring chamber 15, or the like.Alternatively, the pressure measuring portion 16 may be a pressuresensor coupled to the second diaphragm 12 or integrally formed with thesecond diaphragm 12 to detect a pressure value based on the degree ofdeformation of the second diaphragm 12. However, the present inventionis not limited thereto, and the pressure measuring portion 16 maymeasure the pressure inside the monitoring chamber 15 in various ways.

FIG. 3A illustrates an experimental environment for experimenting acorrelation between a pressure change appearing in the monitoringchamber according to the driving of the pump and a pressure changemeasured in the transport target fluid. A pressure sensor was disposedon one side of each of the transport chamber and the monitoring chamberfor the experiment, and the pressure was measured in each of thetransport chamber and the monitoring chamber after driving the pumpingportion 13. At this time, the pump was used as an electroosmotic pump,and the pumping portion of FIGS. 2A(i) and 2A(ii) was used, and avoltage of 2.5 V was alternately applied to the electroosmotic pump,every 30 seconds.

FIG. 3B illustrates an experimental result of FIG. 3A. A dotted lineillustrates the pressure change measured in the pressure sensor providedon a transport chamber side, and a thick solid line illustrates thepressure change measured in the pressure sensor provided on a monitoringchamber side. In this case, since the positive pressure and the negativepressure are alternately generated in the pump, the pressure change isrepresented by a wave (that is, a swing wave) pattern having anamplitude and a period.

As illustrated in FIG. 3B, the pressure changes measured respectively inthe transport chamber and the monitoring chamber appear in forms ofswing waves with opposite polarities in the same period. This is becauseat least a part of the first and second diaphragms 11 and 12 movesforward or backward, so that the capacities of the transport chamber andthe monitoring chamber increase or decrease oppositely. However, it canbe seen that an intermediate value of the swing wave corresponding tothe transport chamber (that is, an average of the pressure values for apredetermined time) and an intermediate value of the swing wavecorresponding to the monitoring chamber are the same or similar. Thatis, it can be seen that the pressure change of the transport targetfluid can be indirectly monitored using the average value of thepressure values measured in the monitoring chamber.

Therefore, the pump 10 according to an example of the present inventioncan monitor the pressure change of the transport target fluid byproviding a single pressure sensor in the monitoring chamber 15 formedon one side of the second diaphragm 12. That is, the pump 10 accordingto an example of the present invention does not include a pressuresensor directly in the flow path, so that the pressure of the transporttarget fluid can be monitored without contaminating the transport targetfluid. This not only makes it possible to monitor the state of the pump10, but also facilitate maintenance of the pressure sensor.

Furthermore, in the pump 10 according to an example of the presentinvention, the pressure value measured in the monitoring chamber 15 isprovided to the system using the pump 10 so that the system caneffectively detect abnormality of the pump 10. Hereinafter, a fluidtransport system (for example, a fluid injection system or a fluidextraction system) using the pump 10 will be described as an example.

FIG. 4 is a block diagram illustrating a configuration of a fluidtransport system 40 using the pump 10 of FIG. 1.

Referring to FIG. 4, the fluid transport system 40 includes the pump 10of FIG. 1; a reservoir 41 in which the transport target fluid is stored;a suction path 42 which is a fluid transport path of the transporttarget fluid and through which the transport target fluid dischargedfrom the reservoir 41 is sucked into the pump 10; a discharge path 45which is a fluid transport path of the transport target fluid dischargedfrom the pump 10; and a control circuit 47 which detects the abnormalityof the pump 10 by monitoring a pressure value measured by the pressuremeasuring portion 16. In addition, the fluid transport system 40 mayfurther include a power supply portion 46 for supplying the electricpower to the pump 10 and the control circuit 47.

The pump 10 includes the first and second diaphragms 11 and 12 which areprovided on both sides of the pumping portion 13 alternately generatingthe positive pressure and the negative pressure, and of which the shapesare changed according to the positive pressure and the negativepressure; the transport chamber 14 which sucks and discharges thetransport target fluid according to the shape change of the firstdiaphragm 11; the monitoring chamber 15 of which the pressure changesaccording to the shape change of the second diaphragm 12; and thepressure measuring portion 16 measuring the pressure of the monitoringchamber 15. Since the configuration of the pump 10 is described abovewith reference to FIGS. 1 to 3B, detailed description thereof will beomitted.

Both ends of the suction path 42 are respectively coupled to thedischarge port of the reservoir 41 and the suction valve 17 (or thesuction port 14 a of the transport chamber 14), to move the transporttarget fluid stored in the reservoir 41 to the transport chamber 14 ofthe pump 10. One end of the discharge path 45 is coupled to thedischarge valve 18 (or the discharge port 14 b of the transport chamber14), and the other end is inserted into a target body to transport (thatis, inject) the transport target fluid to the target body. For example,the discharge path 45 may include a catheter, a cannula, an infusionneedle, or the like to be injected into the target body.

The reservoir 41 is a storage container for storing the transport targetfluid, which is formed of a material that can block external gas andions, and of which one side is coupled to the suction path 42 todischarge the transport target fluid in synchronization with the drivingof the pump 10. That is, when the negative pressure is generated by thedriving of the pump 10, the suction valve 17 is opened to move thetransport target fluid stored in the reservoir 41 to the suction valve17 through the suction path 42. On the contrary, when the positivepressure is generated, the suction valve 17 is closed to stop themovement of the transport target fluid. In this case, since thedischarge valve 18 is opened, the transport target fluid may be injectedinto the target body through the discharge path 45 coupled to thedischarge valve 18.

FIG. 5 is a view for explaining a principle of the movement of thetransport target fluid in the fluid transport system 40 according to anexample of the present invention. In FIG. 5, it is assumed that thepumping portion 13 of FIGS. 2A(i) and 2A(ii) is used.

Referring to FIG. 5, when a negative voltage is applied to the firstelectrode 21 and a positive voltage is applied to the second electrode22 of the pumping portion 13, the negative pressure is generated. By thenegative pressure, the transport target fluid is moved in a direction{circle around (1)}. At this time, the discharge valve 18 is closed, sothat the negative pressure is not transmitted to the discharge path(45).

On the contrary, when a positive voltage is applied to the firstelectrode 21 and a negative voltage is applied to the second electrode22 of the pumping portion 13, the positive pressure is generated in theopposite direction by a reversible electrochemical reaction. Therefore,the transport target fluid sucked into the transport chamber 14 is movedin a direction {circle around (2)} through the discharge valve 18. Atthis time, the suction valve 17 is blocked, so that the positivepressure is not transmitted to the reservoir 41. Therefore, thetransport target fluid moved in the direction {circle around (2)} ismoved to the discharge path 45 to be injected into the target body.

On the other hand, the suction path 42 and the discharge path 45 may beformed of circular tubes (or pipes) of various materials capable ofmoving the transport target fluid but are not limited thereto. Inaddition, coupling means may be provided at both ends of (that is,coupling portions to the reservoir 41 and the suction valve 17,respectively) the suction path 42 and the other end (that is, a couplingportion to the discharge valve 18) of the discharge path 45, and eachO-ring (not illustrated) may be coupled thereto to remove a gap.

The power supply portion 46 is electrically connected to the controlcircuit 47 and the pump 10 to supply the electric power to a motor (notillustrated) or an electrode (not illustrated) of the pumping portion 13by control of the control circuit 47.

For example, in a case in which the pump 10 is an electroosmotic pump,the power supply portion 46 may be implemented by including a DC supplydevice (not illustrated) for supplying a DC voltage to each of the firstelectrode 21 and the second electrode 22 illustrated in FIGS. 2B(i) and2B(ii), to alternately supplying the polarities of the voltage, and aswitching device (not illustrated) for alternately switching polaritiesof the DC voltage supplied to each of the first and second electrodes 21and 22, at every predetermined time. Therefore, the voltage applied toeach of the first electrode 21 and the second electrode 22 may bechanged to the opposite polarity at every predetermined time. However,the present invention is not limited to the above-described example, andthe power supply portion 46 may be implemented as an AC supply device(not illustrated) for supplying a stirring current at a constant cycle.

The control circuit 47 includes one or more circuit elements formonitoring the abnormality of the pump 10 based on the pressure valueprovided from the pressure measuring portion 16. For example, thecontrol circuit 47 may be implemented as a field-programmable gate array(FPGA) or an application specific integrated circuit (ASIC). On theother hand, in an implementation example, the control circuit 47 and thepower supply portion 46 may be mounted on a printed circuit board (PCB).

FIG. 6 is a flowchart illustrating a method of detecting the abnormalityof the pump 10 by the control circuit 47 according to an example of thepresent invention.

First, the control circuit 47 drives the pump 10 (S60). The controlcircuit 47 controls the power supply portion 46 to alternately supplyvoltages having different polarities to the pumping portion 13 of thepump 10. Accordingly, the pumping portion 13 alternately generates thepositive pressure and the negative pressure, thereby changing the shapesof the first and second diaphragms 11 and 12. In other words, at least apart of the first and second diaphragms 11 and 12 is moved forward orbackward in the same direction as the positive pressure and the negativepressure are alternately generated.

As the shapes of the first and second diaphragms 11 and 12 arerepeatedly deformed (that is, moving forward or backward), the transporttarget fluid is sucked and discharged in the transport chamber formed onone side of the first diaphragm 11. In addition, the control circuit 47receives a pressure value from the pressure measuring portion 16provided in the second diaphragm 12 (S61).

The control circuit 47 detects the abnormality of the pump 10 based onthe pressure value measured by the pressure measuring portion 16. Forexample, the control circuit 47 may detect non-operation of the pumpingportion of the pump and the blockage of the fluid path based on a changepattern of the pressure value measured for a predetermined time and anaverage value of the pressure values measured for the predeterminedtime. Here, the predetermined time may correspond to an alternatingcycle of the power supply applied alternately to the pump 10 but is notlimited thereto.

More specifically, the control circuit 47 detects whether or not thechange pattern of the pressure value measured for a predetermined periodcorresponds to a preset pattern (S62). In this case, as described abovewith reference to FIG. 3B, the preset pattern may be a wave (that is, aswing wave) having an amplitude and a period equal to or greater than apreset intensity.

If the change pattern of the pressure value does not correspond to thepreset pattern, the control circuit 47 determines that the pumpingportion 13 is not operated (S63), and then performs an error process(S69). Here, the fact that the change pattern of the pressure value doesnot correspond to the preset pattern (that is, the swing wave) meansthat the pumping portion 13 is not operated so that the positivepressure and the negative pressure are not alternately generated. Thatis, in a case in which the change pattern of the pressure value appearsin a form of a straight line or a curve without period and/or amplitude,the control circuit 47 may determine that the pumping portion 13 is notoperated. In addition, the error process is a program executed by thecontrol circuit 47 when an error occurs in the fluid transport system 40and may include one or more instructions for performing at least one ofuser notification and system state analysis. For example, the programmay notify a notification device (not illustrated) such as a speaker, adisplay, or an LED included in the fluid transport system 40 of the factthat the pump 10 is not operated or may notify a terminal of a user ofthe fact through a communication portion (not illustrated). Stateinformation of the power supply portion 46 may be read to analyze thepower supply state to the pump 10.

However, in step S62, in a case in which the change pattern of thepressure value corresponds to the preset pattern, the control circuit 48determines that the pumping portion 13 of the pump 10 is normallyoperated, and then calculates the average value of the pressure valuesmeasured for a predetermined time (S64). For example, the controlcircuit 47 may calculate the average value of the pressure valuesmeasured for a predetermined time, or calculate an intermediate valuebetween a highest value and a lowest value of the pressure valuesmeasured for a predetermined time.

Thereafter, the control circuit 47 detects whether or not the flow pathis blocked by comparing the average value with a threshold range. In acase in which blockage occurs on the discharge path side of the pump 10,the transport target fluid is not normally sucked into the pump 10 or isnot normally discharged. Therefore, the pressure of the transportchamber 14 in the pump 10 is increased, and thereby the first diaphragm11 moves backward (that is, deformed in the direction toward themonitoring chamber 15 based on FIG. 1) by the pressure of the transportchamber 14 regardless of the operation of the pumping portion 13. Thiscauses the gas or the fluid in the pumping portion 13 to move backward,thereby moving the second diaphragm 12 backward. As a result, thepressure in the monitoring chamber 15 becomes abnormally high.

On the contrary, in a case in which blockage occurs on the suction pathside, the transport target fluid cannot be normally sucked into the pump10, so that the pressure in the transport chamber 14 is decreased. Thiscauses the first diaphragm 11 to move forward (that is, deformed in thedirection toward the liquid chamber 14 based on FIG. 1), and the gas orthe fluid in the pumping portion 13 to continuously move forward.Accordingly, the second diaphragm 12 moves forward regardless of theoperation of the pumping portion 13, and the pressure in the monitoringchamber 15 is abnormally decreased. The control circuit 47 detectswhether or not the flow path is blocked by using whether or not thepressure change in the monitoring chamber 15 is outside a criticalrange.

Specifically, the control circuit 47 determines (S66) that the blockageoccurs in the discharge path of the transport target fluid based on thepump 10 when the average value of the pressure values is equal to orgreater than the critical range for a predetermined time (S65), and theerror process is performed (S69). In other words, the control circuit 47determines that the blockage of the flow path occurs in the dischargepath 45 and/or the discharge valve 18 and performs the error processcorresponding thereto. In this case, as described above, the errorprocess may perform at least one of the user notification and the systemstate analysis, and thus a detailed description thereof will be omitted.

Alternatively, if the average value of the pressure values is less thanor equal to the threshold range for a predetermined time (S67), thecontrol circuit 47 determines that blockage occurs in the suction pathof the transport target fluid based on the pump 10 (S68), and performsthe error process (S69). In other words, the control circuit 47determines that the blockage of the flow path occurs in the suction path42 and/or the suction valve 17 and performs the error processcorresponding thereto.

On the other hand, if the change pattern of the pressure value for apredetermined time corresponds to the preset pattern, and the averagevalue of the pressure values is within the threshold range, the controlcircuit 47 may repeat the process of S61 or below.

In addition, the preset pattern and the threshold range are valuesexperimentally determined based on the case in which the abnormalityoccurs in the fluid transport system and may be preset values in amanufacturing step.

On the other hand, in the above description, the fluid transport systeminjects the fluid into the target body, but as described above, thefluid transport system may extract the fluid from the target body. Inthis case, the discharge path described above is, for example, amicrofiltration (MF) probe, an ultrafiltration (UF) probe, or the like,and functions as the suction path. The suction path functions as thedischarge path and can discharge the transport target fluid extractedfrom the target body to the outside or move the transport target fluidto the reservoir.

FIGS. 7 to 10 are examples of experimental results of detecting thenon-operation of the pumping portion and blockage of the flow path usingthe fluid transport system according to an example of the presentinvention.

FIG. 7 illustrates the fluid transport system used in the experiment. Inthis case, the pump was the electroosmotic pump, the pumping portion ofFIGS. 2A(i) and 2A(ii) was used, and the pressure sensor was attached tothe outside of an upper end of the electroosmotic pump to measure thepressure value. In this case, a voltage of 2.5 V is alternately appliedto the electroosmotic pump at 30 second intervals, and theelectroosmotic pump was configured to suck/discharge the liquid of thereservoir at 30 second intervals. In addition, a stopper was located inthe flow path to simulate the blockage of the flow path.

FIG. 8 illustrates a pressure change in a case in which the operation ofthe electroosmotic pump is artificially stopped, as an experimentalresult of detecting the non-operation of the pumping portion using thefluid transport system of FIG. 7. As illustrated in FIG. 8, it can beseen that when the electroosmotic pump normally operates (that is, 0 to55 seconds), a pressure change pattern of a wave form appears by drivingthe electroosmotic pump, but after the electroosmotic pump isartificially stopped, a linear pressure change appears.

FIGS. 9 and 10 illustrate experimental results of detecting the blockageof the flow path using the fluid transport system of FIG. 7. In FIG. 9,the stopper was located in the catheter to artificially block thecatheter after about 60 seconds. Accordingly, it can be seen that thepressure value measured after about 60 seconds gradually increases. InFIG. 10, the stopper was moved to the suction path side of theelectroosmotic pump to artificially block the suction path after about10 seconds. Accordingly, it can be seen that the pressure value measuredafter about 10 seconds was decreased.

As described above, the fluid transport system using the pump accordingto an example of the present invention moves the transport target fluidon one side of the first diaphragm 11, and forms an air layer of aclosed system on one side of the second diaphragm 12 to monitor thepressure in the air layer. Therefore, it is possible to easily detectthe non-operation of the pump and the blockage of the flow path of thesystem.

A method of operating the fluid transport system according to an exampleof the present invention described above may be implemented in a form ofa recording medium including instructions executable by a computer, suchas a program module executed by a computer. The computer readable mediummay be any available media that can be accessed by the computer andincludes all volatile and nonvolatile media, and removable andnon-removable media. In addition, the computer readable medium mayinclude a computer storage medium. The computer storage medium includesall volatile and nonvolatile media, and removable and non-removablemedia implemented in any method or technology for storing informationsuch as computer readable instructions, data structures, programmodules, or other data.

Although the system and method of the present invention are described inconnection with specific examples, some or all of their configurationelements or operations may be implemented using a computer system havinga general hardware architecture.

It will be appreciated that the description described above of thepresent invention is intended for illustration, and it will beunderstood by those skilled in the art that the present invention may beeasily modified in other specific forms without changing the technicalspirit or essential features of the present invention. Therefore, itshould be understood that the examples described above are exemplary inall respects and not restrictive. For example, each configurationelement described as a single type may be implemented in a distributedmanner, and similarly, the configuration elements described asdistributed may be implemented in a combined form.

The scope of the present invention is illustrated by the followingclaims rather than the detailed description, and all changes ormodifications derived from the meaning and scope of the claims and theirequivalents should be construed as being included in the scope of thepresent invention.

What is claimed is:
 1. An electroosmotic pump comprising: a pumpingportion alternately generating a positive pressure and a negativepressure by a reversible electrochemical reaction; a first diaphragmwhich is provided on one side of the pumping portion and of which ashape is changed as the positive pressure and the negative pressure arealternately generated; a transport chamber which is provided on one sideof the first diaphragm, and sucks and discharges a transport targetfluid corresponding to the deformation of the first diaphragm; a seconddiaphragm which is provided on the other side of the pumping portion andof which a shape is changed as the positive pressure and the negativepressure are alternately generated; and a monitoring chamber which isprovided on one side of the second diaphragm and of which a pressurechanges corresponding to the deformation of the second diaphragm.
 2. Theelectroosmotic pump according to claim 1, further comprising: a pressuremeasuring portion measuring a pressure change of the monitoring chamber.3. The electroosmotic pump according to claim 1, wherein one surface ofthe transport chamber is formed with a suction port and a discharge portthrough which the suction and discharge of the transport target fluidare performed, and wherein a suction valve and a discharge valve forallowing or blocking the flow of the transport target fluid are coupledto the suction port and the discharge port, respectively.
 4. Theelectroosmotic pump according to claim 3, wherein the suction valve isclosed when a positive pressure is generated and is opened when anegative pressure is generated, and wherein the discharge valve isopened when the positive pressure is generated and is closed when thenegative pressure is generated.
 5. The electroosmotic pump according toclaim 3, wherein the suction valve and the discharge valve are checkvalves.
 6. The electroosmotic pump according to claim 2, wherein thepressure measuring portion is a pressure sensor that is provided in themonitoring chamber and detects a pressure of the monitoring chamberbased on at least one of a capacity change, a magnetic force change, aresistance displacement, and a voltage displacement of the monitoringchamber as the second diaphragm is deformed.
 7. The electroosmotic pumpaccording to claim 2, wherein the pressure measuring portion is apressure sensor that detects a pressure of the monitoring chamber basedon a deformation degree of the second diaphragm.
 8. The electroosmoticpump according to claim 1, wherein the pumping portion includes a firstelectrode and a second electrode provided on both sides of a membraneinstalled in, a fluid path portion through which a first fluid moves,and alternately generates a positive pressure and a negative pressure aspolarities of voltages are alternately supplied to the first electrodeand the second electrode, and wherein the first electrode and secondelectrode are formed of a porous material to allow movement of the firstfluid.
 9. The electroosmotic pump according to claim 8, wherein thepositive pressure and negative pressure are generated by a reversibleelectrochemical reaction in first electrode and second electrode, andwherein the reversible electrochemical reaction of first electrode andsecond electrode is caused by movement of cations in a direction ofcharge balancing.
 10. The electroosmotic pump according to claim 9,wherein each of the first electrode and the second electrode isrepeatedly consumed and regenerated by the reversible electrochemicalreaction.
 11. The electroosmotic pump according to claim 8, wherein thefirst electrode and the second electrode include a conductive polymer inwhich an anionic polymer is mixed.
 12. The electroosmotic pump accordingto claim 8, wherein the first electrode and the second electrode includecarbon nanostructures.
 13. The electroosmotic pump according to claim 7,wherein the first electrode and the second electrode include metaloxides selected from the group consisting of oxide (MnOx), cobalt oxide(CoOx), nickel oxide (NiOx), ruthenium oxide (RuOx), and compositesthereof.
 14. A fluid transport system using a pump provided with aplurality of diaphragms, the fluid transport system comprising: a pumpincluding a first diaphragm and a second diaphragm which are provided onboth sides of a pumping portion alternately generating a positivepressure and a negative pressure by a reversible electrochemicalreaction, and of which shapes are changed according to the positivepressure and the negative pressure, a transport chamber which sucks anddischarges a transport target fluid according to the shape change of thefirst diaphragm, and a monitoring chamber of which a pressure changesaccording to the shape change of the second diaphragm; a reservoir inwhich the transport target fluid is stored; a suction path that is afluid transport path through which the transport target fluid dischargedfrom the reservoir is sucked to the pump; a discharge path that is afluid transport path of the transport target fluid discharged from thepump; and a control circuit detecting abnormality of the pump bymonitoring a pressure value measured by the pressure measuring portion.15. The fluid transport system according to claim 14,wherein the pumpincludes a pressure measuring portion measuring a pressure of themonitoring chamber.
 16. The fluid transport system according to claim14, wherein the control circuit detects non-operation of the pumpingportion of the pump and blockage of the fluid path based on a changepattern of the pressure value measured for a predetermined time and anaverage value of the pressure values measured for the predeterminedtime.
 17. The fluid transport system according to claim 16, wherein thecontrol circuit determines that the pumping portion of the pump normallyoperates when the change pattern of the pressure value corresponds to apreset pattern, and determines that the pumping portion of the pump isnot operated when the change pattern of the pressure value does notcorrespond to the preset pattern, and wherein the preset pattern is awave form having a preset amplitude and period.
 18. The fluid transportsystem according to claim 16, wherein the control circuit determinesthat the discharge path is blocked when the average value of thepressure values is equal to or greater than a threshold range.
 19. Thefluid transport system according to claim 16, wherein the controlcircuit determines that the suction path is blocked when the averagevalue of the pressure values during the predetermined time is equal toor less than a threshold range.
 20. The fluid transport system accordingto claim 14, wherein a suction port and a discharge port are formed onone surface of the pump to suck and discharge the transport targetfluid, and wherein a suction valve and a discharge valve for allowing orblocking the flow of the transport target fluid are coupled to thesuction port and the discharge port, respectively.
 21. The fluidtransport system according to claim 14, wherein one end of the suctionpath is coupled to the discharge port provided on one side of thereservoir and the other end is coupled to the suction valve, and whereinone end of the discharge path is coupled to the discharge valve and theother end is injected to a target body.
 22. The fluid transport systemaccording to claim 20, wherein the discharge path is at least one of acatheter, a cannula, and an infusion needle.
 23. The fluid transportsystem according to claim 20, wherein at least a part of each of thefirst diaphragm and the second diaphragm is moved toward the monitoringchamber as the negative pressure is generated in the pump, and is movedtoward the transport chamber as the positive pressure is generated inthe pump.
 24. The fluid transport system according to claim 14, whereinthe pumping portion of the pump includes a first electrode and a secondelectrode provided on both sides of a membrane, a fluid path portion,and alternately generates a positive pressure and a negative pressure aspolarities of voltages are alternately supplied to the first electrodeand the second electrode, and wherein the first electrode and the secondelectrode are formed of a porous material to allow movement of thefluid.
 25. The fluid transport system according to claim 24, wherein thepositive pressure and the negative pressure are generated by reversibleelectrochemical reactions in first electrode and second electrode, andwherein the reversible electrochemical reactions of first electrode andsecond electrode are caused by movement of cations in a direction ofcharge balancing.